Eight methods of stabilizing hooks for operating overhead traveling cranes

As a crane driver, stabilizing the hook is one of the basic skills for actual operation, and it is an indispensable work link in completing each lifting cycle. The so-called stable hook means that the crane driver stabilizes the hook or the object that is swaying due to various reasons during the hoisting process . The editor of our factory will explain to you the complete set of stable hook operation skills under different conditions when operating the overhead traveling crane .

In the work of operating the crane, there are basically eight methods for stabilizing the hook: namely, the stabilizing hook that swings back and forth, the stabilizing hook that swings from side to side, the stabilizing hook for starting, the stabilizing hook on the spot, the stabilizing hook for running, the stabilizing hook for parking, and the stabilizing jitter. Hook and stable arc hook, etc.

1. The stable hook

that swings back and forth When the hanging object swings back and forth, it swings back and forth in the direction of the trolley track.

The method of stabilizing this kind of sway: You can start the trolley to follow the car in the direction of the swing of the hanging object. If you follow the car in a timely and appropriate amount, the sway can be eliminated by following the car at one time. If the sway cannot be completely eliminated in one follow-up, you can follow the vehicle back once according to the above method until the sway is completely eliminated.

2. Stable hook that swings from side to side

When the hanging object swings from side to side, it swings back and forth in the direction of the cart track.

The way to stabilize this swing is to start the cart to follow the vehicle in the direction of the swing of the hanging object. When the hanging object is close to the maximum swing range (the hanging object will swing back to this range), stop following the car, so that the hanging object is in the vertical position. The following speed and the following distance should be determined according to the swing position of the hanging object and the swing amplitude of the hanging object when starting to follow the car. In the same way, if the sway is not completely eliminated after following the car once, you can follow the car once. If the following speed and following distance are selected appropriately, the hanging object can be stabilized by following the car 1 or 2 times.

3. Start the car and stabilize the hook

The starting and stable hook is the key to ensure balance during operation. When the big or small car starts, especially when it starts suddenly and quickly shifts, the car body has moved forward for a certain distance S. The hanging object is connected to the car body by a flexible wire rope, and it lags behind the car due to the inertia of the hanging object. The body is a certain distance S, so that the hanging object is relatively separated from the original stable equilibrium position OG perpendicular to produce swing, as shown in the figure

Schematic diagram of lifting hook

a) get up b) stop c) get up a second time

The heavier the suspended object and the faster the lift, the more severe the swing. Therefore, when the big or small car is started, it should be accelerated gradually, striving for stability, so that the swing of the hanging object is reduced. In addition, when the weight of the crane is large and the vehicle is lifted quickly, when the crane is lagging behind the car body when starting to drive, turn the handle of the cart or trolley to the zero position to brake it, and wait for the crane to swing forward. And when it crosses the vertical line OG of the relative equilibrium position between the hanging object and the car body, immediately start following the car forward. If the timing of following the car is well grasped and the speed of the car is selected appropriately, the car body and the hanging object can be in the position of the OG vertical line without relative movement, that is, running at the same speed, which can eliminate the swing of the hanging object when starting the car.

4. In-situ stable hook

If the body of the big or small car has reached the scheduled parking place, but due to improper operation, too fast, or too strong braking, the hanging object does not stop, but swings back and forth or left and right. In this case, start It is extremely improper to drop the hook to unload the hanging objects. At this time, the unloading of the hanging objects is not only inaccurate, but also extremely unsafe and prone to accidents.

In this case, the crane driver should adopt the method of stabilizing the hook in place, as shown in the figure.

When the hanging object swings forward (or left), start the trolley (or cart) to follow the vehicle forward (or left) to half of the maximum swing of the hanging object, and then start the crane (or trolley) when the hanging object swings back ) Follow the car backwards, this is the key point of in-situ stable hook operation. According to the braking condition of the vehicle body, properly grasp the swing angle of the hanging object, and by following the car back and forth, generally 1 to 2 times can stabilize the hanging object in the position where it should be parked.

Schematic diagram of in-situ stabilization hook

a) Get off the car b) Follow the car forward c) Return to follow the car

5. Running stable hook

When the hanging object swings forward during operation, the gear position of the controller should be increased along the swing direction of the hanging object to increase the speed of the vehicle and the operating mechanism to follow the swing of the hook. When the hanging object swings back, the gear position of the controller should be reduced to reduce the vehicle speed, and the hanging object can keep up with the running angle of the vehicle body to reduce the swing back range of the hanging object.

During operation, by repeatedly accelerating, decelerating, and following the car several times, the crane and the running mechanism can run smoothly at the same time.

6.

Although the suspension hook is very stable during start-up and operation, if the parking method is not mastered during parking, the swing of the suspension during parking will often occur. At this time, the crane driver is required to use the method of stopping and stabilizing the hook to eliminate the swing of the hanging object, as shown in the figure.

When the suspended object is running smoothly, the relative speed between the suspended object and the car body is zero and moves at the same speed. When the parking brake is about to reach the pre-parking position of the suspended object, the vehicle body will stop within a short distance due to mechanical braking. The speed moves forward, resulting in the swinging movement of the hanging object with the hanging point as the center, the distance between the hanging point and the center of gravity G as the radius, and the vertical line 0G as the axis of symmetry.

The method to eliminate this kind of sway is: within a certain distance before the crane is away from the scheduled parking position, the controller handle should be pulled back to the zero position one by one, and the crane should be braked appropriately for 1 to 2 times while the crane is gradually decelerating. When the hanging object is swaying in the forward direction, immediately follow the car with a low speed gear for 1 to 2 times to stop the hanging object smoothly at the pre-stop location.

7. Stable shaking hooks

often encountered shaking hooks during the lifting process of overhead cranes. The shaking hooks show that the hanging object swings back and forth greatly, and the hook shakes several times within one swing angle of the hanging object at a small angle. The reasons for the jitter are: the length of the wire ropes of the hanging objects are different; the center of gravity of the hanging objects is off; the hook is not aligned with the center of gravity of the hanging objects during operation.

It is difficult to stabilize this kind of shaking hook. The method of stabilizing the shaking hook is: when the hanging object swings to the front slowly and greatly, and the hook swings quickly at a small angle, when the direction of the hook shaking and the hanging object swings greatly When the direction is the same, quickly follow the hook, that is, quickly push the controller handle back to the zero position. When the hanging object swings back, when the hook shakes back at a small angle, follow the hook quickly and push the controller handle back to the zero position quickly. In this way, every time you go back and forth with the hook, the swing angle of the jitter will be reduced a lot. If the above-mentioned car following operation sequence is mastered skillfully and the operation is proper, it usually only takes 2 to 3 times to stabilize the hook.

8. Stable arc hook

During lifting or starting, improper operation or the action of some external factors will cause the hanging object to produce an arc-shaped curve movement, that is, an arc hook.

The operation method of stabilizing this arc hook is: adopt the comprehensive movement following method of large and small vehicles, that is, follow the movement direction of the hanging object and the curvature of the hanging object movement curve, manipulate the control handles of the large and small vehicles, and change the speed gear of the controller. Make the trolley produce the corresponding curve movement, can eliminate the swing of the arc-shaped hanging object.

The driver who operates the crane must be proficient in the operation skills of the stable hook under various conditions of the crane, and operate the crane safely.